potential

This package provides functions to compute the potential model as defined by Stewart (1941). Several options are available to customize the model, for example it is possible to fine-tune the distance friction functions or to use custom distance matrices. Some computations are parallelized to improve their efficiency.

Installation

From GitHub

Development version / unstable

require(remotes)
remotes::install_github("riatelab/potential")

Demo

library(sf)

## Linking to GEOS 3.7.1, GDAL 3.1.2, PROJ 7.1.0

library(potential)
library(cartography)
# create a regular grid
y <- create_grid(x = n3_poly, res = 20000)

# compute potentials
pot <- mcpotential(
  x = n3_pt, y = y,
  var = "POP19",
  fun = "e", span = 75000,
  beta = 2, limit = 250000, 
  ncl = 2
)
y$pot <- pot / max(pot) * 100

# create equipotential areas
equipot <- equipotential(y, var = "pot", mask = n3_poly)

# map potentials
opar <- par(mar = c(0, 0, 1.2, 0), bg = "#b5bece", no.readonly = TRUE)
choroLayer(equipot, var = "center", breaks = seq(0,100,length.out = 11), 
           col = hcl.colors(10, 'teal'),
           border = "#121725", legend.pos = "bottom", 
           lwd = .2, legend.title.txt = "Potential Intensity",
           legend.horiz = T)
layoutLayer(title = "Potentials of Population", 
            col = "#121725", coltitle = "#4dB8da",
            sources = "© EuroGeographics for the administrative boundaries and © Eurostat for data",
            horiz = F, postitle = "center", scale = F)
par(opar)

Note

This package provides access to the revamped potential-related functions initially offered by SpatialPosition.

References

Stewart, John Q. 1941. “An Inverse Distance Variation for Certain Social Influences.” Science 93 (2404): 89–90. https://doi.org/10.1126/science.93.2404.89.